> "I’ve been in this business for a long while, and life span is probably one of the most weakly heritable traits I’ve ever studied," Dr. McGue said. Evidently

> "I’ve been in this business for a long while, and life span is probably one of the most weakly heritable traits I’ve ever studied," Dr. McGue said. Evidently "extreme longevity" is more heavily dependent on genetics than non-exceptional lifespans: "Perls and coworkers originally found that the survival ratio for siblings of centenarians versus siblings of 73-year-olds was about fourfold for ages 80–94 (79). In a more recent assessment involving 444 centenarian families, these investigators found that, compared with the U.S. 1900 cohort, male and female siblings of centenarians were at least 17 and 8 times as likely to attain age 100, respectively (80). Similar findings of a much stronger heritability of unusual longevity have been obtained by Kerber et al., who demonstrated an increased recurrence risk for siblings for surviving to extreme ages (81), and Gudmundsson et al., who found that the first-degree relatives of probands who live to an extremely old age are twice as likely as controls to survive to the same age (82)." [1] _ 1. Annu Rev Med. 2005;56:193-212. Quote is from p205. http://pi.edu.pk/donald/genetics.of.longevity.and.aging.pdf http://pi.edu.pk/donald/genetics.of.longevity.and.aging.pdf